Add an option to limit the HRTF's IR size

alc/hrtf.cpp

@@ -342,9 +342,6 @@ void BuildBFormatHrtf(const HrtfStore *Hrtf, DirectHrtfState *state,
             Hrtf->delays[idx[0]][1]*blend[0] + Hrtf->delays[idx[1]][1]*blend[1] +
             Hrtf->delays[idx[2]][1]*blend[2] + Hrtf->delays[idx[3]][1]*blend[3]);
 
-        const size_t irSize{Hrtf->irSize};
-        ASSUME(irSize >= MIN_IR_SIZE);
-
         /* Calculate the blended HRIR coefficients. */
         double *coeffout{al::assume_aligned<16>(&res.hrir[0][0])};
         std::fill(coeffout, coeffout + HRIR_LENGTH*2, 0.0);
@@ -1264,7 +1261,7 @@ al::vector<std::string> EnumerateHrtf(const char *devname)
     return list;
 }
 
-HrtfStore *GetLoadedHrtf(const std::string &name, ALuint devrate)
+HrtfStore *GetLoadedHrtf(const std::string &name, const char *devname, const ALuint devrate)
 {
     std::lock_guard<std::mutex> _{EnumeratedHrtfLock};
     auto entry_iter = std::find_if(EnumeratedHrtfs.cbegin(), EnumeratedHrtfs.cend(),
@@ -1362,9 +1359,9 @@ HrtfStore *GetLoadedHrtf(const std::string &name, ALuint devrate)
         rs.init(hrtf->sampleRate, devrate);
         for(size_t i{0};i < irCount;++i)
         {
+            HrirArray &coeffs = const_cast<HrirArray&>(hrtf->coeffs[i]);
             for(size_t j{0};j < 2;++j)
             {
-                HrirArray &coeffs = const_cast<HrirArray&>(hrtf->coeffs[i]);
                 std::transform(coeffs.cbegin(), coeffs.cend(), inout[0].begin(),
                     [j](const float2 &in) noexcept -> double { return in[j]; });
                 rs.process(HRIR_LENGTH, inout[0].data(), HRIR_LENGTH, inout[1].data());
@@ -1383,6 +1380,15 @@ HrtfStore *GetLoadedHrtf(const std::string &name, ALuint devrate)
         hrtf->sampleRate = devrate;
     }
 
+    if(auto hrtfsizeopt = ConfigValueUInt(devname, nullptr, "hrtf-size"))
+    {
+        if(*hrtfsizeopt > 0 && *hrtfsizeopt < hrtf->irSize)
+        {
+            hrtf->irSize  = maxu(*hrtfsizeopt, MIN_IR_SIZE);
+            hrtf->irSize -= hrtf->irSize % MOD_IR_SIZE;
+        }
+    }
+
     TRACE("Loaded HRTF %s for sample rate %uhz, %u-sample filter\n", name.c_str(),
         hrtf->sampleRate, hrtf->irSize);
     LoadedHrtfs.emplace_back(LoadedHrtf{fname, std::move(hrtf)});

alc/hrtf.h

@@ -89,7 +89,7 @@ struct AngularPoint {
 
 
 al::vector<std::string> EnumerateHrtf(const char *devname);
-HrtfStore *GetLoadedHrtf(const std::string &name, ALuint devrate);
+HrtfStore *GetLoadedHrtf(const std::string &name, const char *devname, const ALuint devrate);
 
 void GetHrtfCoeffs(const HrtfStore *Hrtf, ALfloat elevation, ALfloat azimuth, ALfloat distance,
     ALfloat spread, HrirArray &coeffs, ALsizei (&delays)[2]);

alc/panning.cpp

@@ -812,8 +812,9 @@ void aluInitRenderer(ALCdevice *device, ALint hrtf_id, HrtfRequestMode hrtf_appr
 
     if(hrtf_id >= 0 && static_cast<ALuint>(hrtf_id) < device->HrtfList.size())
     {
+        const char *devname{device->DeviceName.c_str()};
         const std::string &hrtfname = device->HrtfList[static_cast<ALuint>(hrtf_id)];
-        if(HrtfStore *hrtf{GetLoadedHrtf(hrtfname, device->Frequency)})
+        if(HrtfStore *hrtf{GetLoadedHrtf(hrtfname, devname, device->Frequency)})
         {
             device->mHrtf = hrtf;
             device->HrtfName = hrtfname;
@@ -822,9 +823,10 @@ void aluInitRenderer(ALCdevice *device, ALint hrtf_id, HrtfRequestMode hrtf_appr
 
     if(!device->mHrtf)
     {
-        auto find_hrtf = [device](const std::string &hrtfname) -> bool
+        const char *devname{device->DeviceName.c_str()};
+        auto find_hrtf = [device,devname](const std::string &hrtfname) -> bool
         {
-            HrtfStore *hrtf{GetLoadedHrtf(hrtfname, device->Frequency)};
+            HrtfStore *hrtf{GetLoadedHrtf(hrtfname, devname, device->Frequency)};
             if(!hrtf) return false;
             device->mHrtf = hrtf;
             device->HrtfName = hrtfname;

alsoftrc.sample

@@ -128,6 +128,13 @@
 #  usage (still less than "full", given some number of active sources).
 #hrtf-mode = full
 
+## hrtf-size:
+#  Specifies the impulse response size, in samples, for the HRTF filter. Larger
+#  values increase the filter quality, while smaller values reduce processing
+#  cost. A value of 0 (default) uses the full filter size in the dataset, and
+#  the default dataset has a filter size of 32 samples at 44.1khz.
+#hrtf-size = 0
+
 ## default-hrtf:
 #  Specifies the default HRTF to use. When multiple HRTFs are available, this
 #  determines the preferred one to use if none are specifically requested. Note